在另一個數據幀變量與值進行比較，並與另一個值

Question

替代他們，我有一個Data.Frame：

Height <- c(169,176,173,172,176,158,168,162,178) 

和另一個參照身高和體重。

heights_f <- c(144.8,147.3,149.9,152.4,154.9,157.5,160,162.6,165.1,167.6,170.2,172.7,175.3,177.8,180.3,182.9,185.4,188,190.5,193,195.6) 
weights_f <- c(38.6,40.9,43.1,45.4,47.7,49.9,52.2,54.5,56.8,59,61.3,63.6,65.8,68.1,70.4,72.6,74.9,77.2,79.5,81.7,84) 
weightfactor_f <- data.frame(heights_f, weights_f) 

我現在需要從在第二個這是最恰當的高度參考第一data.frame匹配高度的值，並給我參考通訊員重量。

我還沒有取得任何成功，因爲我一直無法找到任何有關匹配值不完全相同的值。

Answer 1

如果我理解你的目標，而不是採取就近值，考慮interpolating通過approx功能。例如：

approx(weightfactor_f$heights_f,weightfactor_f$weights_f,xout=Height)$y 
#[1] 60.23846 66.44400 63.85385 62.95600 66.44400 50.36000 59.35385 53.96923 
#[9] 68.28400 

Answer 2

你可以這樣做：

Height<- c(169,176,173,172,176,158,168,162,178) 
heights_f<- as.numeric(c(144.8,147.3,149.9,152.4,154.9,157.5,160,162.6,165.1,167.6,170.2,172.7,175.3,177.8,180.3,182.9,185.4,188,190.5,193,195.6)) 
weights_f<- as.numeric(c(38.6,40.9,43.1,45.4,47.7,49.9,52.2,54.5,56.8,59,61.3,63.6,65.8,68.1,70.4,72.6,74.9,77.2,79.5,81.7,84)) 

df = data.frame(Height=Height, match_weight= 
      sapply(Height, function(x) {weights_f[which.min(abs(heights_f-x))]})) 

即在Height每個條目，做which.min(abs(heights_f-x)發現在heights_f向量的相應元素，並獲取從weights_f向量中的相應條目。

---

輸出：

Height match_weight 
1 169   61.3 
2 176   65.8 
3 173   63.6 
4 172   63.6 
5 176   65.8 
6 158   49.9 
7 168   59.0 
8 162   54.5 
9 178   68.1 

Answer 3

z <- vector() 
for(i in 1:length(Height)) { 
z[i] <- weightfactor_f$weights_f[which.min(abs(Height[i]-weightfactor_f$heights_f))] 
} 

Answer 4

library(dplyr) 

略有不同結構，以可再現的例子：

Height <- data.frame(height = as.numeric(c(169,176,173,172,176,158,168,162,178))) 

其餘部分是相同的：

heights_f<- as.numeric(c(144.8,147.3,149.9,152.4,154.9,157.5,160,162.6,165.1,167.6,170.2,172.7,175.3,177.8,180.3,182.9,185.4,188,190.5,193,195.6)) 
weights_f<- as.numeric(c(38.6,40.9,43.1,45.4,47.7,49.9,52.2,54.5,56.8,59,61.3,63.6,65.8,68.1,70.4,72.6,74.9,77.2,79.5,81.7,84)) 
weightfactor_f<- data.frame(heights_f,weights_f) 

然後，舍入到最接近的整數：

weightfactor_f$heights_f <- round(weightfactor_f$heights_f, 0) 

然後，只需：

left_join(Height, weightfactor_f, by = c("height" = "heights_f")) 

輸出：

height weights_f 
1 169  NA 
2 176  NA 
3 173  63.6 
4 172  NA 
5 176  NA 
6 158  49.9 
7 168  59.0 
8 162  NA 
9 178  68.1